1. Technical Field
The present application relates to a method for correcting a floating-type magnetic head device mounted in a hard disk device.
2. Description of the Related Art
A floating-type magnetic head device includes a load beam that swings and extends over a rotating hard disk (recording medium), a head body (slider), and a flexure having an elastically flexible tongue piece fixed on a surface of the head body adjacent to the recording medium. When the rotation of the disk is stopped, the bottom surface of the head body comes in contact with the recording surface of the disk due to an elastic force of the load beam. When the rotation of the disk is started, air is introduced so as to flow between the head body and the disk surface along the moving direction of the disk, so that the head body floats over the disk surface due to a floating force associated with the air flow, as applied on the bottom surface of the head body.
In the floating-type magnetic head device, in order to precisely control the horizontal position of the head body and to apply a predetermined load to the magnetic head device, various correcting methods have been proposed. For example, techniques for correcting the shape (corresponding amount to a pitch angle or a roll angle) of the flexure so as to correct the position of the head body are disclosed in JP-A-2000-339894, JP-A-2001-357644 (U.S. Pat. No. 6,977,788B2), and JP-A-2002-15410. Also, techniques for deforming the load beam so as to adjust the magnitude of the load are disclosed in JP-A-1-227279, JP-A-2002-170351 (U.S. Pat. No. 6,823,581B2), JP-A-2002-260358 (U.S. Pat. No. 6,711,929B2), and JP-A-2004-82161 (US-A1-2004-037011).
However, even when the magnetic head device is corrected by such correcting methods, variations in floating height or in load (gram load) of the head body relative to the disk are generated in a mounted state. Strictly speaking, the purpose of correcting the floating-type magnetic head device is to minimize the variations in the floating height or in the gram load of the head body. It has been difficult to sufficiently correct the device by conventional correcting methods.
The present applicant has proposed a novel method for correcting the load beam (Japanese Patent Application No. 2005-88959). The method measures the amount of deformation of the load beam in the mounted state, particularly the deformation in a roll-angle direction. The load beam is corrected by bending the load beam based on the deformation amount in the direction where the roll angle approaches zero. The correcting method includes the steps of temporarily mounting the floating-type magnetic head device so as to float the head body over a rotating disk equivalent surface in a temporarily mounted state (same as the mounted state, but write/read operations are not performed in the temporarily mounted state); detecting a roll-angle corresponding amount at the front end of the load beam in the temporarily mounted state; and bending the load beam based on the roll-angle corresponding amount at the front end of the load beam in the direction where the roll angle at the front end of the load beam approaches zero.